Here is who has done what on homework grading:

HW #	A-G	H-P	Q-Z

1	Hao	Sasha	Nathan
2	Hao	Sasha	Nathan
3	Anton	Nathan	Hao

and the extrapolation to subsequent HW's:

4	Nathan	Hao	Anton
5	Hao	Anton	Nathan
6	Anton	Nathan	Hao
7	Nathan	Hao	Anton
8	Hao	Anton	Nathan
9	Anton 	Nathan	Hao